1 /*
2 * Copyright (C) 2016, Google Inc.
3 * and other copyright owners as documented in the project's IP log.
4 *
5 * This program and the accompanying materials are made available
6 * under the terms of the Eclipse Distribution License v1.0 which
7 * accompanies this distribution, is reproduced below, and is
8 * available at http://www.eclipse.org/org/documents/edl-v10.php
9 *
10 * All rights reserved.
11 *
12 * Redistribution and use in source and binary forms, with or
13 * without modification, are permitted provided that the following
14 * conditions are met:
15 *
16 * - Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 *
19 * - Redistributions in binary form must reproduce the above
20 * copyright notice, this list of conditions and the following
21 * disclaimer in the documentation and/or other materials provided
22 * with the distribution.
23 *
24 * - Neither the name of the Eclipse Foundation, Inc. nor the
25 * names of its contributors may be used to endorse or promote
26 * products derived from this software without specific prior
27 * written permission.
28 *
29 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
30 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
31 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
32 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
33 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
34 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
35 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
36 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
37 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
38 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
39 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
40 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
41 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
42 */
43
44 package org.eclipse.jgit.internal.ketch;
45
46 import static org.eclipse.jgit.internal.ketch.KetchReplica.State.OFFLINE;
47
48 import java.util.ArrayList;
49 import java.util.Collection;
50 import java.util.Collections;
51 import java.util.List;
52
53 import org.eclipse.jgit.annotations.Nullable;
54 import org.eclipse.jgit.lib.ObjectId;
55
56 /**
57 * A snapshot of a leader and its view of the world.
58 */
59 public class LeaderSnapshot {
60 final List<ReplicaSnapshot> replicas = new ArrayList<>();
61 KetchLeader.State state;
62 long term;
63 LogIndex headIndex;
64 LogIndex committedIndex;
65 boolean idle;
66
67 LeaderSnapshot() {
68 }
69
70 /**
71 * Get unmodifiable view of configured replicas.
72 *
73 * @return unmodifiable view of configured replicas.
74 */
75 public Collection<ReplicaSnapshot> getReplicas() {
76 return Collections.unmodifiableList(replicas);
77 }
78
79 /**
80 * Get current state of the leader.
81 *
82 * @return current state of the leader.
83 */
84 public KetchLeader.State getState() {
85 return state;
86 }
87
88 /**
89 * Whether the leader is not running a round to reach consensus, and has no
90 * rounds queued.
91 *
92 * @return {@code true} if the leader is not running a round to reach
93 * consensus, and has no rounds queued.
94 */
95 public boolean isIdle() {
96 return idle;
97 }
98
99 /**
100 * Get term of this leader
101 *
102 * @return term of this leader. Valid only if {@link #getState()} is
103 * currently
104 * {@link org.eclipse.jgit.internal.ketch.KetchLeader.State#LEADER}.
105 */
106 public long getTerm() {
107 return term;
108 }
109
110 /**
111 * Get end of the leader's log
112 *
113 * @return end of the leader's log; null if leader hasn't started up enough
114 * to begin its own election.
115 */
116 @Nullable
117 public LogIndex getHead() {
118 return headIndex;
119 }
120
121 /**
122 * Get state the leader knows is committed on a majority of participant
123 * replicas
124 *
125 * @return state the leader knows is committed on a majority of participant
126 * replicas. Null until the leader instance has committed a log
127 * index within its own term.
128 */
129 @Nullable
130 public LogIndex getCommitted() {
131 return committedIndex;
132 }
133
134 /** {@inheritDoc} */
135 @Override
136 public String toString() {
137 StringBuilder s = new StringBuilder();
138 s.append(isIdle() ? "IDLE" : "RUNNING"); //$NON-NLS-1$ //$NON-NLS-2$
139 s.append(" state ").append(getState()); //$NON-NLS-1$
140 if (getTerm() > 0) {
141 s.append(" term ").append(getTerm()); //$NON-NLS-1$
142 }
143 s.append('\n');
144 s.append(String.format(
145 "%-10s %12s %12s\n", //$NON-NLS-1$
146 "Replica", "Accepted", "Committed")); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
147 s.append("------------------------------------\n"); //$NON-NLS-1$
148 debug(s, "(leader)", getHead(), getCommitted()); //$NON-NLS-1$
149 s.append('\n');
150 for (ReplicaSnapshot r : getReplicas()) {
151 debug(s, r);
152 s.append('\n');
153 }
154 s.append('\n');
155 return s.toString();
156 }
157
158 private static void debug(StringBuilder b, ReplicaSnapshot s) {
159 KetchReplica replica = s.getReplica();
160 debug(b, replica.getName(), s.getAccepted(), s.getCommitted());
161 b.append(String.format(" %-8s %s", //$NON-NLS-1$
162 replica.getParticipation(), s.getState()));
163 if (s.getState() == OFFLINE) {
164 String err = s.getErrorMessage();
165 if (err != null) {
166 b.append(" (").append(err).append(')'); //$NON-NLS-1$
167 }
168 }
169 }
170
171 private static void debug(StringBuilder s, String name,
172 ObjectId accepted, ObjectId committed) {
173 s.append(String.format(
174 "%-10s %-12s %-12s", //$NON-NLS-1$
175 name, str(accepted), str(committed)));
176 }
177
178 static String str(ObjectId c) {
179 if (c instanceof LogIndex) {
180 return ((LogIndex) c).describeForLog();
181 } else if (c != null) {
182 return c.abbreviate(8).name();
183 }
184 return "-"; //$NON-NLS-1$
185 }
186 }